Add initial code for sadis-server.

Change-Id: Iaa8d6ddf888c04abc8eee5933c0c7401c0094394
diff --git a/handlers.go b/handlers.go
new file mode 100644
index 0000000..791073e
--- /dev/null
+++ b/handlers.go
@@ -0,0 +1,120 @@
+// Copyright 2018 Open Networking Foundation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package main
+
+import (
+	"strconv"
+	"encoding/json"
+	"net/http"
+	"github.com/gorilla/mux"
+)
+
+
+func (c *Config) getSubscriberHandler(w http.ResponseWriter, r *http.Request) {
+	vars := mux.Vars(r)
+	sadisRequestID := vars["id"]
+
+	log.Infof("Looking for object %s in XOS database", sadisRequestID)
+
+	defer r.Body.Close()
+
+	subscribers := subscribers{}
+
+	log.Debug("Checking subscribers")
+
+	err := c.fetch("/xosapi/v1/rcord/rcordsubscribers", &subscribers)
+	if err != nil {
+		log.Errorf("Unable to retrieve subscriber information from XOS: %s", err)
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+
+	}
+
+	for _, sub := range subscribers.Subscribers {
+		if sub.OnuSerialNumber == sadisRequestID {
+			log.Infof("Found subscriber with ID %s", sub.OnuSerialNumber)
+			sadisSubscriber := sadisSubscriber{
+				ID: sub.OnuSerialNumber,
+				CTag: sub.CTag,
+				STag: sub.STag,
+				NasPortID: sub.NasPortID,
+				CircuitID: sub.CircuitID,
+				RemoteID: sub.CircuitID, // TODO get a proper value here
+			}
+
+			json, e := json.Marshal(&sadisSubscriber)
+			if e != nil {
+				log.Errorf("Unable to marshal JSON: %s", e)
+				http.Error(w, e.Error(), http.StatusInternalServerError)
+				return
+			}
+			w.Write(json)
+			return
+		}
+	}
+
+	log.Debug("Checking devices")
+
+	devices := oltDevices{}
+
+	err = c.fetch("/xosapi/v1/volt/oltdevices", &devices)
+	if err != nil {
+		log.Errorf("Unable to retrieve device information from XOS: %s", err)
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+
+	}
+
+	for _, device := range devices.OltDevices {
+		devID := device.Host + ":" + strconv.Itoa(device.Port)
+		if devID == sadisRequestID {
+			log.Infof("Found OLT device with ID %s", devID)
+			sadisDevice := sadisDevice{
+				ID: devID,
+				Uplink: toInt(device.Uplink),
+				HardwareID: "de:ad:be:ef:ba:11", // TODO do we really need to configure this?
+			}
+
+			json, e := json.Marshal(&sadisDevice)
+			if e != nil {
+				log.Errorf("Unable to marshal JSON: %s", e)
+				http.Error(w, e.Error(), http.StatusInternalServerError)
+				return
+			}
+			w.Write(json)
+			return
+		}
+	}
+
+	log.Infof("Couldn't find object %s in XOS database", sadisRequestID)
+
+	http.NotFound(w, r)
+}
+
+func toInt(value string) int {
+	r, _ := strconv.Atoi(value)
+	return r
+}
+
+func (c *Config) fetch(path string, data interface{}) error {
+	resp, err := http.Get(c.connect + path)
+	if err != nil {
+		return err
+	}
+
+	defer resp.Body.Close()
+	decoder := json.NewDecoder(resp.Body)
+	err = decoder.Decode(data)
+	return err
+}